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SBRT and Pancreas Cancer La Belle et la Bête Gert Meijer
SBRT and Pancreas Cancer
La Belle et la Bête
Gert Meijer
la Bête
Controversial role of radiotherapy
• OS was not improved with CRT, 16.5 m vs. 15.3 m
(HR = 1.03[0.79-1.34], p=0.83)
How about the radiotherapy in LAP07?
• All patients treated with 3D-CRT
• Margin on GTV was 3 cm sup-inf and 2 cm radially
• No prophylactic RT to the nodes
• The investigators conclude in the presentation that RT still has an important role in LAP, however they advocate for novel delivery modalities
How about the SBRT?
• patient friendly • non-invasive • hypofractionated
• high dose to central • low dose to organs at risk
How about the SBRT?
How about the SBRT?
How about the SBRT?
Can we cure all patients? - NO!
Can we cure a few patients? - Maybe…. How about palliation? - Hopefully…
poor target definition
poor OAR definition
poor online image guidance
target moves
OARs move too
closeby radiosenstive OARs
What hurdles to take?
poor target definition
poor OAR definition
poor online image guidance
target moves
OARs move too
closeby radiosenstive OARs
What hurdles to take?
poor target definition
poor OAR definition
poor online image guidance
target moves
OARs move too
closeby radiosenstive OARs
What hurdles to take?
Heerkens et al. R&O 2014
poor target definition
poor OAR definition
poor online image guidance
target moves
OARs move too
closeby radiosenstive OARs
What hurdles to take?
Pancreas cancer has been identified as one of key tumor sites within MR-linac consortium
? Sept 2015 Houston
MRI-guided SBRT with for locally advanced pancreatic cancer: a feasibility and safety study Add MRI for target definition and definition organs at risk
1
MRI-guided SBRT with for locally advanced pancreatic cancer: a feasibility and safety study Use gold markers for image guidance during treatment
Acknowledgements Eelco Lens AMC Amsterdam
2
MRI-guided SBRT with for locally advanced pancreatic cancer: a feasibility and safety study Use abdominal corset to reduce motion and measure residual motion with cine MRI
3
MRI-guided SBRT with for locally advanced pancreatic cancer: a feasibility and safety study Create SBRT plan with 3-mm GTV-PTV margins to 3x8Gy
4
MRI-guided SBRT with for locally advanced pancreatic cancer: a feasibility and safety study Blur dose with respiratory motion kernel to estimate effect breathing
breathing pattern 3 x breathing pattern 10 x breathing pattern
5
MRI-guided SBRT with for locally advanced pancreatic cancer: a feasibility and safety study
6
Results
Results
80% intrafraction motion < 3 mm
• 26 patients
– 23 LAPC
– 3 LRPC
• mean age 70 (range 50 -85)
• 13 patients died
• 7 patients developed metastases (1 is still alive)
• No treatment related grade 3 toxicity within 90 days
• One grade 2 pancreatitis due to seed procedure
Results
• Our SBRT regimen is very well tolerated
• No improvement in LC/survival
• Increase dose!
So.....
4D MRI Coronal
Sagittal
Transverse
CC
mo
tio
n (
mm
)
Pancreatic motion
1) Stemkens B et al. ISMRM, 2013 2) Roujol S et al. IEEE TMI, 2011
Flow chart
Pre
-be
am
imag
ing
Rad
iati
on
Transform 3D volume, based on 2D images, using
motion model
Full FOV 3D motion
information (x,y,z,t)
4D MRI acquisition (x,y,z,φ) Motion model
Acquire 2D cine MR images
Warped 3D volume (model)
2D coronal slice (acquired)
So in the end with the MR-linac we are working towards dose deliveries to pancreas tumors with the same accuracies as we currently do in brain Hopefully this will result in a clinical benefit for (a subset of) LAPC patients
Acknowledgements: Hanne Heerkens Bjorn Stemkens Rob Tijssen Marco van Vulpen
Baudouin Denis de Senneville Nico van den Berg Jan Lagendijk Eelco Lens (AMC)
Beth Erickson (MCW) William Hall (MCW)
